Solar street light working principle and circuit diagram <br> Solar street light controller made with PIC12F675 single chip microcomputer
The figure is a solar street light controller circuit made by PIC12F675 microcontroller. The PIC 12F 675 is an 8-pin microcontroller with six I/O ports, an internal RC oscillator (oscillation frequency of 4MHz), four 10-bit A/D converters, and a comparator. The controller is stable. Reliable and low power consumption.
1 . working principle
PIC 12F675 controls battery over-charging, over-discharging, on and off street light function, timing lighting, black automatic lighting, delayed lighting, automatic tracking and lighting, street lighting test control function, LED indication function, etc. .
The battery power supply system is composed of the battery BT1, the battery overcharge control execution field effect transistor 01, and the three-terminal voltage regulator U1; Q2, Q4. It consists of discharge control; K1 manual, R_GM1 light control automatic light-on system, battery voltage divider resistor, and light-emitting indicator diode. The solar panel voltage is input by interface J3. After anti-backfill diode D1, it is divided into two ways. After being regulated by U1 LM 78L 05, it provides working power for PIC 12F675 microcontroller, and the other is charged by FB fuse. After the MCU is powered on, the hardware circuit consisting of Rf and Cf is first reset. Then the software controls U2 3 pin GP4 to output high level, let Q4 turn on, Q2 cut off, control system stops discharging, then detects the voltage dividing value on U27 pin GP0, indirectly detects and judges through internal A/D conversion and software operation. Whether the battery is under voltage or overvoltage. If the battery is overcharged, the U2 pin GP5 outputs a high level through software to make Q1 turn on. Short-circuit the solar panel, stop charging the battery, and light the “overcharge” indicator LED2; if no overcharge occurs, U2 2 pin GP5 outputs a low level to allow the battery to charge. By detecting the voltage division value on the photoresistor R_GM1 connected to the U2 6 pin GP1, it is judged whether it has been "tall, the time of the open lamp is reached". If the preset light-on point is reached, the software controls the u2 3-pin GP4 output low. The level is such that Q4 is turned off and 02 is turned on to illuminate the street light. If the light is not turned on, the program returns and the above parameters are cyclically detected.
K1 is the manual light on button. When K1 is pressed, the street light is on. The single chip microcomputer detects the partial pressure value on the photoresistor R_GM1 to determine whether it is "day black", if it is dark. Then, the street lamp is illuminated according to the design requirements. If not, the MCU enters the "test" function of the street lamp controller: after 2 minutes, the street lamp automatically goes out.
2 . Note Because the programming of the single-chip microcomputer is very flexible, the "light-on point" is used here as the light-on marker. This point can be time. It can also be the "degree" of darkness. If the time is defined, the street light can be timed from this time, and it will be extinguished after lighting for several hours; if it is dark, the street light can be turned on after the darkness. After that, it can be timed out, or it can be judged to be off after dawn. Everything is chosen by the software designer.
Solar street lamp working principle and circuit diagram II
The circuit principle is shown in the figure. The circuit consists of a battery overcharge control circuit composed of U5 as the core, a battery voltage indicating circuit composed of U 4A to U4D as the core, a display voltage button switch KS1 circuit, a battery over-discharge control circuit composed of U1B, and a U1A. The light-on detection control circuit, the U2-based turn-on and time-out light-off and the second-on light-off timing control circuit, and the output control circuit composed of the control transistor Q2 drive relay are composed. Now they are introduced as follows.
(1) Overcharge, overdischarge detection protection Part of the solar panel or array is input from pin 1 of the socket CZ1 and applied to the positive pole of the anti-recharge diode D2. The negative pole of D2 is connected to the positive pole of the 12V battery, that is, the 3rd leg of CZ1. When the controller is powered on initially, the U52 pin is low due to the action of C4, the 3 pin outputs a high level, and Q7 is turned on; Q8 is turned off, allowing the solar cell to charge the battery. When the battery is charged less than 14 . At 4V, the series voltage divider circuit consisting of R13 and (R38 X R39) is sent to U5 2, 6 when the voltage is lower than 2 / 3 U5, that is, less than 6V, the circuit maintains the charging state; with the extension of charging time The battery voltage gradually rises. When the voltage of U5 2, 6 is higher than the 2 / 3 U5 supply voltage, the U53 pin outputs a low level, Q7 is cut off, Q8 is turned on, the solar panel is discharged, and the battery is stopped. . When the U53 pin outputs a low level, its 7-pin is turned on, which is equivalent to incorporating the 1140 into the circuit. At this time, the voltage division ratio of the circuit is: R38+ R39/R40/IRl3+(R38+R39)/R40, it is not difficult to calculate when the battery voltage is lower than the set value of 13V. The circuit state is flipped again, and the U53 pin outputs a high level to allow the battery to charge.
(2) Light-on detection method and control solar panel is a good photosensitive element, and its output current and voltage can change with the intensity and illumination of the received light. The controller uses this principle to open and close. Light controlled. The PVin input voltage of the solar panel is divided into series by R5 and R6; it is added to the U 1A 2 pin of the op amp, and its 3 pin is connected to the voltage dividing point of R9 and R8+VR1. During the daytime, the solar panel emits a high voltage under the illumination of sunlight. After being divided by R5 and R6, the voltage of the U1A2 pin of the op amp is higher than 3, U 1A1 pin outputs low level, Q1 is cut off, U2 is unpowered. The voltage does not work, Q2 is cut off, the relay does not pick up, the system has no output voltage, and the street light does not work. As the sky darkens, the solar panel output voltage decreases. The voltage of UlA 2 pin also decreases synchronously. When the voltage of U1A2 pin is lower than 3 pin, the comparator flips, U 1A 1 pin outputs high level, Q1 turns on, timing circuit U2 gets electricity, Q2 turns on, JDQ1 pulls in. Light up the street light. In the figure, VR1 sets the adjustment potentiometer for the street light to turn on the light, and adjusts VRl to set the street light to be illuminated at different times. DW1 is a clamp diode that prevents the U 1A 2 pin input voltage from being too high and damaged due to excessive voltage received by the solar panel during the day. C1 is the storage capacitor, which prevents the U1A2 pin voltage from suddenly igniting and illuminating the street light. R14 is the feedback resistor. Its role is to make U 1A a hysteresis comparator. Prevent and avoid U1A from oscillating near the light-on point and repeatedly turn the lights on and off.
(3) Street lamp delay circuit lighting and extinction control circuit delay control circuit selects CD4541BE programmable timing control chip, it has low power consumption, built-in programmable frequency divider circuit, ** frequency division level is 65536 class.
The controller adjusts the timing of the timing of turning on the lights and timing off the lights: 2 . 093 hours-11 . 93 hours. Adjusted by V: R2 and VR3 respectively.
(4) Battery stop discharge priority control circuit If the battery voltage is lower than its allowable termination discharge value when the street lamp is to be lit or is lit, Q4 is turned on. At this time, regardless of whether the U 1A output is high or not, Q1 is turned off, thereby protecting the battery from over-discharge damage.
(5) Battery voltage indicating circuit In order to let the field care and maintenance personnel know and grasp the state of the battery in time, the controller is provided with an LED battery voltage indicating device, and the number of the LLED lighting indicates the level of the battery voltage.
2 . Found in the circuit debugging production. The actual state transition point of the NE555 time base circuit, that is, the 1 / 3V ( : C and 2 / 3VCC state of the flip trip point is not strictly following the theoretical value. 14.4V overcharge control can be achieved by adjusting the resistor R13. R13 The actual requirement can be met by changing the designed 100kΩ to 120k Ω. Similarly, the battery indication voltage can be calibrated by adjusting VR4.
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